Process control systems often employ fluid devices such as, for example, pumps, fluid valves, etc. to control the flow of process fluids. For example, a fluid valve typically includes a fluid flow control member that is disposed within a fluid path of a valve body. A valve stem (e.g., a sliding stem) operatively couples an actuator to the flow control member, which moves the flow control member relative to an orifice or valve seat to control fluid flow through the fluid path. The actuator (e.g., a pneumatic actuator) moves the flow control member between an open position at which the flow control member moves away from the valve seat to allow fluid flow through the valve and a closed position at which the flow control member engages the valve seat to restrict or prevent fluid flow through the valve.
In sanitary systems, a fluid valve often includes a flow control member that comprises a diaphragm to provide a sanitary condition. The diaphragm is composed of an elastomeric material that includes a peripheral edge that is clamped or compressed between a bonnet and a valve body to provide a seal between the valve body and the bonnet. When coupled to the valve body, the bonnet provides a compressive load to the peripheral edge of the diaphragm. In operation, the diaphragm may be subjected to substantial temperature and/or pressure fluctuations of a process fluid flowing through the valve body that may cause the diaphragm to expand and/or contract between the bonnet and the valve body. Such expansion and/or contraction of the diaphragm may cause the compressive load imparted to the peripheral edge of the diaphragm to be greater than a maximum allowable load, thereby causing the diaphragm to buckle, deform or otherwise become damaged.